1. Field of the Invention
The invention relates to aircraft and particularly to the propeller and engine drive system therefor. More particularly, the invention relates to an aircraft drive system having two propellers, each driven by a separate engine and in which all of the drive system components are mounted on a single tubular member which is attached to the aircraft frame.
2. Description of the Prior Art
It has long been known in the aeronautical field that increased aircraft performance and efficiency can be obtained by a propeller drive system having two propellers mounted in a coaxial relationship with respect to each other and rotatably driven in opposite directions. Various propeller and engine drive system arrangements have been proposed for driving such coaxially mounted propellers in opposite directions. These prior systems required expensive and special types of engines, complicated engine mounting arrangements and associated pulley drive systems, crossed belt arrangements, gears and a plurality of rotary shafts to achieve the opposite rotation of the dual propellers. These complicated prior arrangements were expensive and added additional weight and components to the aircraft which reduced the efficiency of the drive system, and increased maintenance and the possibility of malfunction. Examples of these prior art dual propeller and engine drive systems are shown in U.S. Pat. Nos. 1,110,489, 1,132,368, 1,793,933, 3,335,979, and 3,470,961.
There is no known dual engine and propeller drive system of which I am aware which mounts both engines, propellers and drive components therefor on a single fixed tubular sleeve member which is mounted on the aircraft frame, and in which the tubular sleeve member forms a support for rotatably mounting one of the propellers with the drive shaft for the other propeller being telescopically rotatably mounted within the interior of the tubular member.